Title:

Spin It To Win It

Specific Question:

Does the amount of rotations you do off a ski jump affect how far you go from the knuckle?

Hypothesis:

It is hypothesisized that a Three sixty would go farther than another spin. 360 was hypothesized to got the farthest because the less spinning you do the farther you will go, this is why 720 will go the least farthest.

Graph of Hypothesis:

Variables:

Independent Variable:

The different of rotations done off a ski jump.

Dependent Variable:

The distance form the knuckle.

Variables That Need To Be Controlled:

The staring point, the jump, skier, same skis, same gear, time period.

Vocabulary List That Needs Explanation

Knuckle;
The transition between the flat and the landing of a jump.

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General Plan

The experiment tested the distance a skier travels off a jump doing three different tricks in the terrain park. The experiment took place at Attitash in the terrain park on Lower Ptarmigan. The trail was marked with flags for every meter after the jump. The skier started at a set point and ski down towards the jump . The skier did a 360 off the jump. After the jump the distance was measured with the flags. The skier repeated the process three times. The skier then went off the jump 540 and the distance was measured with the flags. The skier repeated the jump three times doing a 540. The process was repeated with a 720. The independent variable in this experiment was the different amount of rotations . The experimenters observed the average distance for each trick. The independent variable was measured by observations made by the experimenters. In order to control the experiment the same skier, equipment and jump was used. Also the experiment was done in the morning to ensure snow conditions. A potential problem could be falling.

Potential Problems And Solutions

snow conditions/indoor ski arena.

Safety Or Environmental Concerns

none

Experimental Design

(add the correct headings from the experimental design page before beginning)

Resources and Budget Table

Materials:
LUKE’S SKIS: ANTIGEN/DIMENSIONS: 116-89-115 RADIUS: 16.0 m WEIGHT 1490 grams
Ski Boots
Bindings:
Snow pants
Jacket
Helmet
Goggles
Poles
Flags
Video Camera
Jump
Measuring Tape

Data Table

Time Line

3/2 complete design and collection of all materials
3/10 run a test of the set up , not collecting data, just seeing if everything works
3/17 run first official trials of expecting , collect first data
3/17 complete all trials of experiment and all data collection
4/2 complete all data analysis
4/2 complete results and conclusion write -up

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Background Research

Physics Of Skiing — Freestyle Skiing

WORK CITED: http://www.real-world-physics-problems.com/physics-of-skiing.html

In the freestyle skiing known as aerial freestyle, a skier performs aerial acrobatics,
spinning and twisting in the air. The basic physics principle at work here is the
conservation of angular momentum. The angular momentum of the skier is determined at
takeoff (from a ramp), and cannot be changed once the skier is airborne. So to make
turns in the air the skier must give himself initial rotation upon takeoff. Once airborne,
the skier can alter his body shape in order to produce an impressive aerial display of
tricks and twists for the crowd, during which his angular momentum remains constant.
The picture below shows an aerial freestyle skier performing an acrobatic trick.

Another type of freestyle skiing is mogul skiing, in which a skier skis over a terrain
covered with many bumps. To minimize the jarring forces acting on him, a mogul skier
rides the bumps using mostly up and down leg movement, like a shock absorber, while
minimizing the movement of his upper body. This keeps his center of mass moving in as
straight a line as possible. And by Newton's Second Law, this keeps the forces acting on
him as low as possible.

Thus, the physics of skiing with regards to mogul skiing, is keeping the acceleration of
the center of mass of the skier minimal to avoid excessive jarring. And this isaccomplished by making the center of mass of the skier move in as straight a line as
possible.
The ability of skis to adapt to a terrain (either for moguls or other types of skiing), is a
function of their torsional stiffness and flexural stiffness. Torsional stiffness is the ability
of the ski to resist twisting along its length. This is related to the ability of the ski to
maintain "biting" contact with the snow. Flexural stiffness is the ability of the ski to
resist bending (such as reverse camber). For riding on harder, or icier snow, a ski with a
greater flexural stiffness is generally desired since it can ride the bumps and undulations
better. For softer snow, a less flexurally stiff ski is usually desired. Clearly, ski stiffness
and adaptability to the terrain is an important consideration in the physics of skiing.
Physics Of Skiing — Ski Maintenance

Ski maintenance also ties into the physics of skiing by optimizing the performance of the ski on the snow,
as explained in the points below:

• Waxing the bottom of skis protects them from wear and water penetration, the latter of which can
damage the skis. Wax also makes the bottom of the skis waterproof, reducing wet-drag (suction)
friction, which is caused when excess water collects at the bottom of the skis.

• The edges of the skis must be kept sharp using a stone grinder, much like skate blades, to allow for
easier turning and stopping.
This concludes the discussion on the physics of skiing

References

http://www.real-world-physics-problems.com/physics-of-skiing.html

Detailed Procedure:

Procedure
1. Set up the video camera at an angle where the filmer will be able to follow the test subject through his jumping.
2 A tape measure will laid out along the landing of the jump and when the subject lands a marker flag with numbers 1-9 written on each flag.
3. The subject would hike up to the starting place 65 feet above the lip of the jump .
4.The starting place will be determined by the speed of the snow on that day.
We will have a starting point marked with pink flags
The subject will line the middle of their boots up to the flags.
place poles parallel with the flags and lean forward and go toward the jump
5. The test subject would ski down to the jump and do a 360, 540 or a 720.
then a flager will be placed mark were the middle of the subjects boots hit the snow.
Video tape will used to check and make sure our eyes are as accurate as the camera.

Video: This is video of how our experiment looked.

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Results

All Raw Data

zx raphs

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Conclusion:

The conclusion to the experiment shows that the rotation done off a jump has little to no effect on the subject’s distance from the knuckle of the jump. The one test subject completed three different rotation off one jump. The subject did each of these rotations three times each. The distance of each trial was measured from the knuckle. The Rotation that went the farthest is 540’, The reason for this is totally random. If the experiment had worked it out the way it was expected to 360’’ should have gone farthest. 540’ should have been second in distance and 720’ in last. There is no reason for for the 540’ to have gone farther than 360’’.

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Discussion:

Benefit to Community and/or Science

The question in the experiment was to find whether or not the number of rotations done off a ski jump affected how far the subject landed past the knuckle.The knuckle is the beginning of the jump. It was hypothesized at the beginning of the experiment that a ‘straight air’ would go farther than any other spin. No straight air was conducted so, it was hypothesized that a 360 degree rotation would go the farthest in place of a straight air. The question was answered, but not the way it was expected. It was found that the rotations completed did not affect how far the subject landed. The data recorded showed absolutely no pattern and was inconsistent for each trial. The reason this happened this way is unknown. The video recorded of each trial showed that all of the control variables stayed the same, including the path taken into the jump. From the starting point to where the subject landed is one tenth of a mile.
The biggest problem faced in this experiment was the weather. On the day the experiment took place it was approximately 80 degrees out. The weather is usually not this warm this time of the year.The snow consistency was like mashed potatoes, meaning wet, sloppy and heavy snow. The snow consistency got sloppier and sloppier as the experiment went on making the speed into the jump slower each time. Originally it was thought that the speed getting slower would have affected by making the distances landed shorter. The distances were scattered in lengths, from 11 feet for 360 and 24 feet for a 540. .

The things needed to conduct the experiment were an iphone, marking flags, gopro (video camera) and a skier with the necessary equipment. The thing that would have been most helpful for this experiment is an indoor ski slope. An indoor ski slope would help conditions stay the same like “http://en.wikipedia.org/wiki/Ski_Dubai”. Another helpful tool would be a speed radar gun to gauge the speed to make sure the same speed is used going into the jump every time. Due to the inconclusive data collected in the experiment it is unclear how the experiment will help or enlighten others. If the experiment had been completed correctly, the jump creators and designers would have found the information useful. This information would help to prevent people getting hurt when spinning and flipping on a jump.

Abstract:

The experiment was to determine if the amount of rotations affects how far a person would go. The independent variable in this experiment was the amount of rotations. The dependent variable was the how far the person went. The amount of rotations did not affect the distance a person would go. For the 720 rotations, the person went 20.3 feet from the knuckle , for the second trial the person went 17.5 feet from the knuckle . For the third trial , the person went 13.1 feet from the knuckle. The average for the 720 rotations was 17.63 feet from the knuckle. For the 540 rotations , the person went 24.9 feet from the knuckle and then in the second trial the person went 11.5 feet from the knuckle. On the third trial the person went 18.20 feet from the knuckle. The average was 18.28 feet from the knuckle. The first trial for the 360 rotation was 14.6 feet from the knuckle. The second trial for the 360 rotation was 11.2 feet from the knuckle. The third trial for the 360 rotation was 15.3 feet from the knuckle. The average for the the 360 rotation was 13.7 feet from the knuckle. The data proves that the amount of rotations did not affect how far a person went off a jump, because the 540 rotation had the highest average distance.